1. Field of the Invention
The invention relates generally to acoustic surface wave energy processors employing acoustic means for processing electrical input signals and yielding modified electrical output signals and, more particularly, concerns transducer means for launching a surface acoustic wave on a non-piezoelectric slab-like element by first launching the surface wave at the surface of a piezoelectric slab-like element spaced apart from the aligned non-piezoelectric slab-like element. A plurality of discrete bars or rails, each rail contacting both wave propagating surfaces of the piezoelectric and non-piezoelectric elements, forms an array providing mechanical contact and energy transfer between the wave propagating surfaces. The periodicity of the rails of the array is arranged to maximize coupling of energy into the second or non-piezoelectric element. Since the reciprocity theorem correctly applies to the structure, the functions of the output and input terminals may be interchanged.
2. Description of the Prior Art
Prior art acoustic wave coupling devices of the kind for transferring energy between non-piezoelectric and piezoelectric surfaces, as will be discussed, have generally lacked the capability of operation with acceptble efficiency or with outputs sufficiently free of distortion at input frequencies above about 50 MHz. Since advancing techniques arising in the surface wave art demand such capability, it is an object of this invention to provide a suitable coupling scheme.